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CYLINDER GRINDING MILL. APPLICATION FILED OCT-25,1915.

1,304,8 1 9'. Patented May 27, 1919.

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OSCAR SODER, OF NIEDERLENZ, SWITZERLAND.

CYLINDER GRINDING-MYILL.

Specification of Letters Patent.

Patented May 27, 1919.

Application filed October 25, 19.15. Serial 170.757,74.

To all whom t may concern: v

Be it known that L-OsoAR SODER, a citizen of the Republic Vof Switzerland, residing at Niederlenz, in Switzerland, have invented certain new and useful Improvements in Cylinder Grinding-Mills; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention, such as will enable others, skilledY in the art to which it apperta-ins to make and use the same, reference being had to the accompanying drawings, and to letters or guresof reference marked thereon, which form a part of this specification.

This invention relates to improvements in cylinder grinding mills of the kind-having a grinding block pressed against the millstone and in which either the grinding block or tlie'cylindrical millstone is moved, while the latter is revolving, to and fro in the axial direction of the millstone, in order to prevent the formation of grooves or channels in the grinding surfaces and secure a good and fine grinding of the material. It has been found by experience that it is particularly advantageous to impart to the millstone said axial to and fro movement and that particularly good results are' obtained, when the ratio between the` speed of this to and fro movement and the speed of revolution of the millstone is such, that all points of the grinding block describe onl the millstone surface curves crossing one another. This has, however, the eect'to cause the millstone to dilate and distort, so that shortly after the mill is put into operation the grinding surfaces touch one anothery only at certain points, and a good and equal ne grinding of the' material is thus not possible. Moreover, there takesv place at-the points touching one another larrinju'rious andK dangerousvproduction of heat. p

The object of the present invention is to eliminate this drawback, and to this end the grinding concave is subdivided lengthwise into a plurality of elements or single parts,

. each of which is pressed separately against the cylindrical millstone, so that the elements lie snugly in contact with the millstone which receives a to and fro movement in its axial direction, even in the case ythat this millstone dilates and distorts; the material being ground in an equal and fine manner, while any too great and dangerous heat production is eliminated.

Two convenient modes of carrying the invention into eifect are shown in the accompanying drawings, in whichy Figure 1 is a front elevation of the grinding mill, i

Y Fig. 2 is a side view of the mill, Fig. 3 is a vertical cross-section on the line A-B of Fig. 1,

Fig.' 4 shows on an enlarged scale a plan View of ai detail and Fig. 5 is a. plan view of a modification.

l denotes the millstone, consisting preferably of'stone and supported in bearings 3. The latter are linedV to the wooden frame 4C of the 'grinding mill. On the shaft 2 lis mounted'a driving pulley 5. 6a, 6b, tic/and 6d denote the different elements or parts of the subdivided grinding concave. On a horizontal shaft 8 supported in bearings fixed to the machine frame are pivotally mounted four arms 7 a, 7 0,7c and 7 d carrying respectively said elements 6, 6", 6c and 6d. A cross-beam 26 is held by means of screwbolts l() at a certain distance from the wooden frame 4. The cross-beam 2G has four threaded apertures, into which are screwed four hand-wheels 22 provided with screw-threaded bosses. In each of the lat-ter there is loosely mounted a bolt 21 screwed into plates 27 fixed to the elements 6a, 6", 6c and Gd of the grinding concave (Fig. The screw-threaded end of each bolt 21 carries av hand-wheel 25. YBetween each screwthreaded boss of the hand-wheel 22 and the plate 27 there is arranged a tension spring 23 and a plate 24Lacting yas an abutment for this spring. Thus, the cross-beam 26 is kept by resilient means at a certain distance from the millstone l and it takes up a'horizontal position. Upon a rotation of one of the hand-wheels 22 the corresponding spring 23 will be tensioned, so that it acts with greater force upon the plate 27, thus pressing the corresponding element of the grinding concave more strongly against the cylindrical millstone l. In order, however, that the spring pressure may ynot act at an unlimited distance upon the element of the grinding concave, there' is provided a hand-wheel 25 permitting an adjustment of the distance of the spring pressure and therefore also an adjustment of the grinding concave element relatively to the grinding depth. This isv particularly of importance when the grinding mill runs on no load.

28 denotes a roll for feeding the material to be ground toward the milling-race. On

that end of the shaft 2, which lies opposite the shaft end carrying the pulley 5, is mounted a small pulley 14 driving a pulley 13 fixed to a shaft 12 having its bearings in the frame 4 of the grinding mill. The shaft 12 is provided with a crank pin 121. To a double armed lever 16 is pivotally connected a crank rod 15 operatively connected to said pin 121. The upper ends of the lever 1G engage a collar 19 surrounding the shaft 2 and arranged between two shoulders 20. rhe double 'armed lever 16 is pivotally mounted on a shaft 18 supported in two brackets 17 fixed to the frame 4. The pulley 14 mounted on the shaft 2 is made of such a size with regard to the pulley 13 and the motion transmitting members 121, 15, 16 are chosen in such a manner that the ratio between the speed of rotation of the millstone and the speed of the to and fro movement of the latter is such, that the millstone is rotated several times, e. g. four times, while it is displaced once to and fro in its axial direction. The number of revolutions of the millstone could, however, as well be increased to six. The result of this is, that all points of the grinding concave describe on the millstone curves crossing each other, thus preventing the formation of grooves.

The manner of operation of the hereinbefore described cylindrical grinding mill is as follows:

Upon a rotation of the millstone 1 in the direction of the arrow shown in Fig. 3, a slow rotary movement is imparted to the pulley 13 and therefore also to the shaft 12. The motion ofthe crank pin 121 of this shaft is thereby transmitted by means of the connecting rod 15 to the double armed lever 16, engaging the collar 19, in such a manner to the shaft 2, that the millstone 1 mounted on this shaft is shifted axially to and fro, so that any formation of grooves in the grinding surfaces is -eliminated and the latter are always kept smooth.

It is evident, that the grinding concave can be subdivided into any number of elements or parts. If desired, there can be provided for each element of the concave an independent feed passage for the material to be ground. Such independent passages may be formed as shown in Fig. 5 by providing a plurality of partitions 29a, 29h, 29, and 29d, in the frame 4 above the feed roll 28, each passage communicating directly with one element of the concave.

IVhat I wish to claim is:

1. A fine grinding cylinder mill comprising a mill stone, means for rotating the latter, a plurality of concaves coperating with said stone to form a space between the concaves and stone continuously diminishing in width in the direction of rotation of said stone, said concaves arranged lengthwise of the stone, a pivot for the concaves parallel to the axis of the millstone and arranged beneath and laterally of said axis, and separate yielding adjusting means for each concave. v

2. A fine grinding cylinder mill, comprising 'a millstone, means for rotating the latter, a plurality of concaves coperating with said stone to lform a space between the concaves and stone continuously diminishing in width inthe direction of rotation of said stone, said concaves arranged lengthwise of thefstone, Va pivot for the concaves'parallel to the axis of the mill-stone and arranged beneath Aand laterally of said axis, separate yielding adjusting means 'for each concave and means Vfor imparting a to-and-fro movement to the millstone during its rotation.

3. A fine grinding cylinder mill, comprising 'amill stone, means for rotating the latter, a plurality of concaves coperating with said stone 'to form aspace between the concaves and stone continuously diminishing in width in the direction lof rotation of said stone, said concaves arranged lengthwise of the'stone, al pivot for the concaves parallel to the axisof the millstone and arranged beneath and laterally of said axis, and separate yielding 'adjusting means for each concave, said means including a spring` to yieldingly hold the concave in grinding position.

4. A fine grinding cylinder mill, comprising a frame, a mill-stone mounted in said frame, means for rotating said stone, a. plurality lof concaves each having a concave surface coperating with said stone, a shaft mounted in said frame parallel to the axis of said stone, below and laterally of said axis, said concaves pivoting on said shaft, adjusting means including yielding means to adjust the concaves to and from said stone and yieldingly hold them in their adjusted position, said concaves forming with the stone a' grinding Vspace continuously diminishing in width under all'conditions of operation, the beginning of said space about at the point where the material is ycaused to leave said Vstone under centrifugal action.

lIn testimony that I claim the foregoing as my invention I have signed lmy name in presence'of two subscribing witnesses.

osoAR soDER.

lVitnesses A ARNOLD LEHNER, CARL GUBLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

